Simulation for CT measurements at a LINAC-based measurement setup for radioactive waste drums

This thesis investigates the response of an X-ray imaging system for the characterization of radioactive waste packages using Monte Carlo simulation. The work is carried out in collaboration with the Belgian Nuclear Research Center (SCK CEN) and is intended to support a project utilizing a refurbished medical linear accelerator to enable radioactive waste assay through computed tomography applications. X-ray imaging techniques are commonly assessed at the level of reconstructed images, while the underlying system response and its dependence on system geometry and configuration remain less systematically explored in this context. Representative imaging configurations are simulated using the GATE simulation toolkit to provide data for response analysis and characterization. Owing to the abstracted nature of the simulation setup, the approach remains independent of specific hardware implementation and allows the investigation of complex geometrical configurations. The system response is characterized through the point spread function and quantified using a set of derived metrics. The methodology is applied to a set of representative configurations to demonstrate how the proposed workflow supports structured parameter scans of geometric and beam-related system settings and the resulting metrics. This work contributes to the development of response-based analysis methodologies for nondestructive assay techniques applied to radioactive waste characterization.